Grinding tool



April 2, 1940.

E. M. McG OVERN ET AL GRINDING TOOL Filed Dec. 17, 1938 2 Sheets-Sheet 1 April 2, 1940. E. M. YMQGOVERN El AL 2,195,493

GRINDING TOOL Filed Dec. 17, 1933 2 Sheets-Sheet 2 j HM/l Mm k\\ A 1 4 53 55 55 35 /0 ATTORNEYS Patented Apr. 2, 1940 UNITED STATES PATENT orncs 2,195,493 GRINDING TOOL Edward M. McGovern and Paul Schrick, Hillside, N. J., assignors to Lempco Products, Inc., Cleveland, Ohio, a corporation of Application December 17,

3 Claims.

This invention relates to a grinding tool suitable for grinding shafts and other round objects to render them truly cylindrical. Our grinding tool, for instance, is well adapted for grinding the crankshafts of automobile engines.

In grinding crankshafts it is desirable to have a separable ring-like frame carrying on its inner periphery spring pressed shoes supporting abrading material. The separation of the frame allows the device to be passed around the crank shaft and then closed, making a complete ring about it, with the abrading material pressed against the shaft, whereupon rotation of the device grinds'the shaft.

The object of our invention is to provide such a device in a simple and efiicient form wherein the shoes and the abrading material carried thereby will be preserved in proper alignment and gradually pressed inwardly as the grinding proceeds.

Another feature of our invention relates to an efiicient construction for readily rotating the grinding shoes while allowing them to move inwardly. t

The invention will become more apparent from the following description, reference being had to the accompanying drawings illustrating a preferred embodiment of the invention.

In the drawings, Fig. 1 is a cross-section of our grinding tool ina plane at right angles to the axis of the shaft to be ground; Fig. 2 is a diagrammatic cross-section of the tool as indicated by the line 2-4 on Fig. 1; Fig. 3 is a view illustrating the tool mounted on a crankshaft and driven by a belt 4 1s a fragmentary radial secone of the grinding shoes and the driving frame, the plane of section being indicated cross-sectional view of the tool on a plane normal to the plane of separation, as indicated by the line 5-5 on Fig. 1

The frame of the grinding tool comprises a split pulley consisting of two half-ring members, In and I I, each of which has formed in its outer periphery a groove l2 adapted to receive a driving belt. The

by a pair of links l3 and I4, each of which is seated in a recess in the members and pinned thereto by two pins i5 and Hi. The pins I5 are permanently attachedso that the two links as shown comprise a rigid part of the member H. The pins it are readily removable to allow separation of the two half-ring members. Each of these latter pins preferably has an enlarged head l1 normally occupying a counterbore in the member Hi. When the pin is slightly shoved out from the opposite .31 secured thereto by screws 32.

. annular frame members which occupy slots 1 of flexible emery are removably connected together shoe where it is clamped by a bar Ohio 1938, Serial No. 246,373

side the head furnishes means for insertion of a screw driver or similar tool to withdraw the pin so that the parts may be separated.

The annular separable frame described carries N two identical arcuate members 30, each of which is faced on its inner periphery by an arcuate shoe The member 30 and the shoe 3i constitute in practice a rigid member, but by making the shoes separable they may be replaced by shoes of different size. to change the working diameter of the tool.

Each of the driven members 30 is formed with a pair of edge flanges 33 extending radially outward to provide a comparatively wide groove between them, in which the frame members In and ll seat, as shown in Fig. 2.

One of the driven members 30 carries rigidly a pair of blades 40 which extend for the full width of the member 30 and project at right angles to the plane of separation of the two members. These blades occupy grooves 4| in the other member 30 with an easy sliding fit. The blades operate to maintain these two members in accurate alignment and at the same time allow one to move The internal members 30 are driven by the and guided in their movement thereby by means of pins l8 on the annular frame 35 in the members 30. The walls of these slots are normal to the plane of separation of the two halves of the device, and thus allow the members 30 and their shoes to move toward or from each other.

The shoes are pressed outwardly by compression springs 50. These springs occupy radial recesses inthe members I and II respectively, and act on inwardly movable plungers bearing against the members ery grooves therein. The springs are compressed by plugs 52 screwed into the radial recesses.

Each shoe 3| carries suitable abrading material. This may readily comprise a strong piece cloth 60, one end of which is acrossthe end of the 62 secured by bent outwardly as at 6|,

screws 63.- h I The two pieces of emery cloth are secured at diametrically opposite regions to the two shoes 3| respectively, as indicated in Fig. 1. When the device is rotated in a direction which will be counter-clock-wise in that figure, the emery cloth travels over the surface of the article being ground and the stresses maintain it smooth on the two shoes at the same time the springs 50 30 at the base of the periphe cal press these shoes inwardly to maintain the grinding action.

In Fig. 3

This tool is Well adapted for shafts f motor vehicles without removing the to remove the pan of the crankshaft housing and detach the connecting rods. Preferably the tool does not fill the entire space between the cranks of a split ring-like driving dein the other shoe whereby the shoes are guided 30 upon movement relative to said frame.

EDWARD M. MCGOVERN. PAUL SCHRICK. 

